User Contributed Notes 3 notes

Since PHP5 upgraded PHP to an OOP language, they CHANGED the metaphor so that when you copy an object, you just get a pointer to it (as in C# and Java) and so therefore they needed to make a way to CLONE objects as well in case you need a REAL copy of the object.

Most cases, clone is not needed, simply because a real copy of an object is usually not mandatory. In special cases, object cloning can be used to save time in porting.

Here is another possible solution for migrating code to php 5 when using $this = 'something' reassignments. In my case, I had several classes with methods that were self-instantiating with static calls. I was able to simply use a different variable: I changed $this to $_this and it worked the same because I copied an instance of the original object by reference using an instantiation factory method:

class DB { function &getInstance() { static $instance = null;

if ($instance === null) { $instance = new DB(); }

return $instance; } ...

In every method needing access to this object I assigned it to a temporary variable by reference:

function doSomething () { $_this =& DB::getInstance();

$_this->doSomethingElse(); $_this->param['id'] = 123; }

Which allows method calls or saving data back to the original object.

I originally created classes like this so I didn't need to keep track of instantiations or global objects. I could just call DB::doSomething() and the object is created dynamically or referenced from an already existing object.